[The immunomodulatory role of sodium]

High salt intake, which is common in the Western world, is the cause of several lifestyle diseases. Recent investigations shed light on novel extrarenal processes, which play role in the maintenance of sodium balance. In the short term, sodium storage of the skin may serve as a buffer against volume overload arising from the osmotic properties of sodium. Increased tissue sodium concentration may also potentiate immune response against infections. In the long run, however, tissue sodium concentration over a certain limit may initiate pathophysiological processes by provoking inflammatory response. Due to the immune modulating role of sodium, the effector cells of the innate as well as the adaptive immune system are activated, while certain regulator cells of the same systems are repressed, ultimately resulting in a proinflammatory state characterized by the imbalance of the immune system. Experiments applying dietary salt overload/salt depletion imply the role of sodium in the initiation/exacerbation of several diseases. Thus the relationship between sodium and the immune system may give an explanation to the pathomechanism of diseases with so far unknown origin such as hypertonia (primary, salt sensitive) or autoimmune diseases - all these putting tremendous pressure on the healthcare system due to their increasing incidence. Orv Hetil. 2019; 160(17): 646-653.